New Physics with Exotic Or Long-Lived Signatures

New Physics with Exotic or Long-lived Signatures

SEARCH Workshop

Oxford University ΛQCD' (GeV) 1 2 3 4 5 2000 50 � /� = � UK �� 40

30 1000 ) 2. September 2016 ) 20 GeV GeV ( ( T B m 500 m

David Curtin 200 10 20 30 40 University of Maryland m200m0 (GeV) 100m 20m Surface Detector

100m (side view) Exotic Physics vs Exotic Signatures Exotic Physics vs Exotic Signatures

Obviously some overlap… However: “mainstream” theories are so for good reasons, but how “exotic” a theory is changes with TIME and DATA!

~~ ~ 0 ~ 0 ~ 0 ~ 0 ~~ ~ ∼ t t production, t → b f f' χ∼ / t → c χ∼ / t → W b χ∼ / t → t χ∼ Status: ICHEP 2016 0 1 1 1 1 1 1 1 1 1 1 pp → gg, g → bb χ1 ICHEP 2016 600 1800 ATLAS Preliminary s=13 TeV -1 ~ 0 ~ 0 -1 Preliminary 12.9 fb (13 TeV) t → t ∼χ / t → W b ∼χ t0L 13.2 fb [CONF-2016-077] CMS [GeV] 1 1 1 1 0 1 ~ 0 -1 miss ∼ χ t → t ∼χ t1L 13.2 fb [CONF-2016-050] 1600 1 1 [GeV] SUS-16-014 (H ) 500 0 1 T Expected m ~ ∼0 -1

∼ χ t → W b χ 1 1 t2L 13.3 fb [CONF-2016-076] SUS-16-015 (MT2) ~ 0 Observed t c ∼ MJ 3.2 fb-1 [1604.07773] m 1→ χ 1400 SUS-16-016 (αT) 1 s=8 TeV, 20 fb-1 Run 1 [1506.08616] 400 1200 Observed limits Expected limits All limits at 95% CL

1000 300 W t

+ m 0 ) < m b 0 ) < 0 ∼ 1 ,χ 800 ∼χ 1 ~ t 1 , 0 ) < m ~ t 1 ∼χ 1 m( ~ , m( t 1 ∆ ∆ ∼0 m( 200 c χ ∆ 600 1

0 b f f' ∼χ 400 1 100

0 200 W b ∼ χ1

0 0 800 1000 1200 1400 1600 1800 2000 200 300 400 500 600 700 800 900

~ ~ mt [GeV] mg [GeV] 1 Exotic Physics vs Exotic Signatures LHC detectors are designed for ﬁnal states that are familiar from our high-energy exploration of the SM: - QCD jets - leptons - photons - b-quarks with ~mm decays Exotic Physics vs Exotic Signatures LHC detectors are designed for ﬁnal states that are familiar from our high-energy exploration of the SM: - QCD jets - leptons - photons - b-quarks with ~mm decays

What is an exotic signature? “Reach” for New Physics in every direction! Anything not that. Mass This mostly involves long-lived BSM states. TeV

- Long-Lived Particle (LLP) mh - macroscopic states (quirks) μm = 10-6m 10m 107m lifetime -7 - ﬁreballs (black holes, ..) (prompt) 10 s 0.1 s c� (m) Exotic Physics vs Exotic Signatures LHC detectors are designed for ﬁnal states that are familiar from our high-energy exploration of the SM: - QCD jets - leptons - photons - b-quarks with ~mm decays

What is an exotic signature? “Reach” for New Physics in every direction! Anything not that. Mass This mostly involves long-lived BSM states. TeV

- Long-Lived Particle (LLP) mh - macroscopic states (quirks) Focus of this talk. μm = 10-6m 10m 107m lifetime -7 - ﬁreballs (black holes, ..) (prompt) 10 s 0.1 s c� (m) Exotic Physics vs Exotic Signatures LHC detectors are designed for ﬁnal states that are familiar from our high-energy exploration of the SM: Mostly weak scale physics. - QCD jets - leptons - photons - b-quarks with ~mm decays Many other dedicated experiments for very light LLPs (SHiP, beamdumps, etc…) What is an exotic signature? “Reach” for New Physics Anything not that. in every direction! We want to make sure we don’t Mass missThis anything mostly while involves the LHC is running! long-lived BSM states. TeV

- Long-Lived Particle (LLP) mh - macroscopic states (quirks) Focus of this talk. μm = 10-6m 10m 107m lifetime -7 - ﬁreballs (black holes, ..) (prompt) 10 s 0.1 s c� (m) Outline

1. Theories with LLPs (From Vanilla to “Exotic”)

2. Charged LLPs (Long lifetimes are “easy”)

3. Neutral LLPs (Long lifetimes are difﬁcult)

4. The MATHUSLA Experiment (Hunting for the oldest particle in the Bible BSM theories!) Theories with LLPs

(just a few examples) Generalities

A state is long-lived if it can only decay via: To observe at the - a small coupling (approx symmetry?) LHC, produce via - a high-scale operator ↔ heavy messengers etc different operator - small phase space (small mass splittings) than decay!

Dark Sectors e.g. Dienes, Su, Thomas 204.4183 Hidden Valleys Dynamical Dark Matter Multi-component Dark Matter SUSY Asymmetric Dark Matter Kaplan, Luty, Zurek 0901.4117 Baryogenesis E.g. late-time decay of meta-stable WIMPs Cui, Sundrum 1212.2973 Neutrino Masses RH Neutrino can easily be long-lived at low mass / small mixing. Antusch, Cazzato, Fischer 1604.02420 Batell, Pospelov, Shuve 1604.06099 Supersymmetry Supersymmetry RPV Couplings generically small (proton decay, flavor violation…) Can be generated dynamically → LLPs generic! Csaki, Kuflik, Volansky, 1309.5957 Csaki, Kuflik, Slone, Volansky, 1502.03096 Mini-Split Heavy sfermions, loop-suppressed gaugino masses. Not entirely natural, but get DM, GUT Arvanitaki, Craig, Dimopoulos, Villadoro 1210.0555 Arkani-Hamed, Gupta, Kaplan, Weiner, Zoraski 1212.6971

Gauge Mediation Minimal versions disfavored by Gravitino LSP Higgs mass but non-minimal ~ “kinked Long-lived � → � + G versions can still be attractive track” 0 (calculable, no ﬂavor problem). Long-lived � → Υ + g Even Vanilla SUSY can be lousy with long- lived states.

But SUSY is becoming increasingly constrained.

This motivates non-minimal versions (e.g. Stealth SUSY) which can also contain LLPs… Fan, Reece, Rudermann 1105.5135, etc … as well as qualitatively different perspectives on Naturalness… Neutral Naturalness

(See also Riccardo’s talk.) Uncolored Top Partners

In SUSY or Little Higgs theories, symmetry which protects the Higgs commutes with SM color → colored top partners → make lots @ LHC!

Can “twist” the theory so that the low-energy top parters are related to tops by an additional discrete symmetry transformation which does not commute with color.

continuous symmetry discrete top quark t SM COLOR symmetry NEUTRAL! top partner T

Folded SUSY (EW-charged stops), Twin Higgs (SM singlet T-partners) hep-ph/0609152 Burdman, Chacko, Goh, Harnik hep-ph/0506256 Chacko, Goh, Harnik Uncolored Top Partners

1. Uncolored top partners avoid LHC constraints!

2. New BSM QCD’ gauge force!

Naturalness motivation for Hidden Valleys! LLPs in Neutral Naturalness

Scenario with Simplest Pheno: top partners (FSUSY, QLH, some FTH) maybe other states

QCD’ glueballs < ~ 60 GeV

Higgs talks to mirror glue via top partner loops:

top partners

Craig, Katz, Strassler, Sundrum 1501.05310 DC, Verhaaren 1506.06141 LLPs in Neutral Naturalness Can produce lots of glueballs in Glueballs are LLPs! Exotic Higgs Decays: visible Higgs mirror mirror SM

glueball max m0 = 10 GeV glueball

κ 0.010 top = m0 = 40 GeV κ partners

for 0.001 m0 = 60 GeV )

++ ++ 0 Log10cτ (meters) of 0 glueball ++ -4 0 10 2000 7 0 -1 → 3 h mirror ( 2

Br 4 glueball 10-5 2500 200 400 600 800 1000 1 ] m∼(GeV) 1500 ] t 2000 Quirky Top Partner Production: -2

emission of soft Twin Higgs photons / glueballs Folded SUSY 1500 6 SM 1000 )[

)[ 5

T pair GeV (

production GeV ( T

via DY or h* t

(PERTURBATIVE) 1000 m

= m -3 T slow Ts p p shower & hadronize 500 (s)quirkonium into two DARK de-excitation T GLUEBALL JETS -4 500 T annihilation to hard mirror gluons -5 (PERTURBATIVE) 0 10 20 30 40 50 60 see also Emerging Jets m0 (GeV) (Schwaller, Stolarski, Weiler)

Craig, Katz, Strassler, Sundrum 1501.05310 DC, Verhaaren 1506.06141 Chacko, DC, Verhaaren 1512.05782 LLPs in Neutral Naturalness Can produce lots of glueballs in Glueballs are LLPs! Exotic Higgs Decays: visible Higgs mirror mirror SM

glueball max m0 = 10 GeV glueball

κ 0.010 top = m0 = 40 GeV κ partners

for 0.001 m0 = 60 GeV )

++ ++ 0 Log10cτ (meters) of 0 glueball ++ -4 0 10 2000 7 0 -1 → 3 h mirror ( 2

Br 4 glueball 10-5 2500 200 LLPs400 can600 be800 the1000 smoking gun 1of ] m∼(GeV) 1500 ] t 2000 Quirky Top Partner Production:naturalness. -2

emission of soft Twin Higgs photons / glueballs Folded SUSY 1500 6 SM 1000 )[

)[ 5

T pair GeV (

production GeV ( T

via DY or h* t

(PERTURBATIVE) 1000 m

Craig, Katz, Strassler, Sundrum 1501.05310 DC, Verhaaren 1506.06141 Chacko, DC, Verhaaren 1512.05782 Searches for Charged LLPs

(includes long-lived BSM hadrons if they make it out of the tracker) Charged LLPs Charged LLPs

They’re not invisible!!! Charged LLPs

They’re not invisible!!!

muon triggers anomalous dE/dX (high or low) time-of-ﬂight track curvature deposition and decay kinked tracks disappearing tracks Searches get easier the longer they live. Limits

Already some results with 13/fb @ 13 TeV

Long lifetime ➝ stable limits (best) Covering all Possibilities?

Current Searches: CMS charged/hadronic LLP search, including q = 1/3 - 8 e ATLAS charged/hadronic LLP search ATLAS searches q = 2 - 6e , for monopoles, and for q =10 - 60 e ATLAS & CMS disappearing tracks searches ATLAS & CMS search for out-of-time decays of stopped particles

LHCb Opportunity? “kinked” + “disappearing” tracks @ ATLAS/CMS ➝ kinked tracks @ LHCb VELO is as close as 0.1cm from beam, without B-ﬁeld!

Missing at ATLAS/CMS: ~ - Kinked Tracks (e.g. � NLSP) - Anomalous curvature (macroscopic quirks) - stable low mass, low charge LLP search? Milli-charged Particles MilliQan Approaching the “neutral LLP” Haas, Hill, zero-charge-limit Izaguirre, drastically decreases sensitivity. Yavin 1410.6816; … We have to catch them with dedicated Letter of intent: detectors. 1607.04669; Searches for Neutral LLPs Neutral LLP Searches

Neutral LLP searches are harder than charged LLP searches, but the signals can still be spectacular. Distinctiveness of Signature in Detector: Heavy Displaced Missing charged track/ > > Decay Energy deposition not yet more like Rule of Thumb for Neutral LLP searches DV + X ⇒ Very little background High quality Something else @ LHC very macroscopic that’s kinda rare displaced vertex (leptons, high-mass, another DV…)

X could be a property of the LLP itself Performed Searches at ATLAS or CMS DV + X ⇒ Very little background High quality Something else @ LHC very macroscopic that’s kinda rare displaced vertex (leptons, high-mass, another DV…) d ≳ cm + X = distinctive LLP decay products (leptons, lepton jets…) X = ‘hard’ LLP: has high mass and decays in tracker X = another DV, and first DV is in Muon System/HCAL (longish lifetime) Performed Searches at ATLAS or CMS DV + X ⇒ Very little background High quality Something else @ LHC very macroscopic that’s kinda rare displaced vertex (leptons, high-mass, another DV…) d > cm + X = distinctive LLP decay productsLiu, Tweedie (leptons, lepton jets…) X = ‘hard’ LLP: has high mass and1503.05923 decays in tracker X = another DV, and first DV is in Muon System/HCAL (longish lifetime) In combination, together with charged LLP and prompt searches, this already gives very significant reach for many theories! Most important required searches DV + X ⇒ Very little background High quality Something else @ LHC very macroscopic that’s kinda rare displaced vertex (leptons, high-mass, another DV…)

1. Need sensitivity for “softer” LLPs, e.g. from exotic Higgs decays, which is a highly motivated LLP production mode ⇒ X = single lepton (Vh) or VBF jets (events are on tape!)

2. X = all of the above, DV with d ~ 0.1mm - cm (repurpose b-tagger? LHCb opportunity?) 3. LLP decay with d >> detector size (also relevant for testing if MET = DM) Most important required searches DV + X ⇒ Very little background High quality Something else @ LHC very macroscopic that’s kinda rare displaced vertex (leptons, high-mass, another DV…)

1. Need sensitivity for “softer” LLPs, e.g. from exotic Higgs decays, which is a highly motivated LLP production mode ⇒ X = single lepton (Vh) or VBF jets (events are on tape!)

2. X = all of the above, DV with d ~ 0.1mm - cm (repurpose b-tagger? LHCb opportunity?) 3. LLP decay with d >> detector size (also relevant for testing if MET = DM) Neutral Naturalness @ HL-LHC

++ Log10cτ (meters) of 0 glueball 2000 7 0 -1 3 2 4 2500

1 ] 1500 ] 2000 Need entire -2 Twin Higgs array of LLP Folded SUSY 1500 6 1000 )[ )[ 5 search strategies GeV ( GeV ( T t Looong DV in 1000 m to cover m -3

top partner top mass lifetime tracker DV in 500 tracker parameter space -4 500 (short!) -5 0 10 20 30 40 50 60

m0 (GeV) glueball mass

DC, Verhaaren 1506.06141 Neutral Naturalness @ HL-LHC

s = 14 TeV, 3000fb-1 (MS)x(MS or IT) DV searches 1500 (VBF h→bb) x (IT, r > 4cm) 2000 in tracker* or (single lepton) x (IT, r > 50μm) ] TLEP Br(h→invisible) ] Muon System

1500 1000 Twin Higgs Folded SUSY *need VBF or )[ )[ 1000

GeV lepton for ( GeV ( T t ∼ m m 500 triggering. top partner top mass 500

0 10 20 30 40 50 60 TeV Top Partner m0 (GeV) Mass Reach glueball mass from LLP searches! DC, Verhaaren 1506.06141 Most important required searches DV + X ⇒ Very little background High quality Something else @ LHC very macroscopic that’s kinda rare displaced vertex (leptons, high-mass, another DV…)

1. Need sensitivity for “softer” LLPs, e.g. from exotic Higgs decays, which is a highly motivated LLP production mode ⇒ X = single lepton (Vh) or VBF jets (events are on tape!)

2. X = all of the above, DV with d ~ 0.1mm - cm (repurpose b-tagger? LHCb opportunity?) 3. LLP decay with d >> detector size (also relevant for testing if MET = DM) LLP Search for Long Lifetimes Probably the best we can do at the LHC: search for a single DV in the ATLAS Muon System.

Very challenging search! Have to obtain fully differential data-driven background estimates.

1605.02742 Andrea Coccaro, DC, Henry Lubatti, Heather Russell, Jessie Shelton Projected Sensitivities: single DV in ATLAS MS

1 0.500 1DV in MS, with BG 0.100 limit

) 0.050 2 DV in MS, no BG XX → h ( min Br 0.010 pT = 120 GeV 0.005 s = 13 TeV 30 fb-1 0.1 1 10 100 1000 cτ (m)

Projected limits of 1DV in MS search far superior at long lifetimes compared to existing 2DV search.

Hopefully will be implemented at run 2!

1605.02742 Andrea Coccaro, DC, Henry Lubatti, Heather Russell, Jessie Shelton Resulting Neutral Naturalness Sensitivity 1605.02742 Andrea Coccaro, DC, Henry Twin Higgs Lubatti, Heather Russell, Jessie Shelton

ΛQCD' (GeV) 1 2 3 4 5 2000 50 � /� = � �� 40

30 1000 1DV in MS 2DV in MS ) ) 20 1DV in IT (r > 50 μm)+lepton GeV GeV ( ( 1DV in IT (r > 4 cm)+VBF jets T B m 500 m Higgs coupling measurements

10 top partner top mass

200 10 20 30 40

m0 (GeV) glueball mass Allows us to probe ~ 5 GeV Glueballs! (very long-lived) Is there any way to detect neutral ultra-long-lived particles (ULLPs) near the BBN bound of c� ≲ 107 - 108 m? LHC Main detectors are limited in their ability to probe *very* long neutral LLP lifetimes. Obvious reason: Geometry LHC Main detectors are limited in their ability to probe *very* long neutral LLP lifetimes. Obvious reason: Geometry But…

Assume ULLPs are produced in exotic Higgs decays with Br ~ 10%

Assume a lifetime near the BBN limit: c� ~ 107m The LHC makes a lot of Higgs bosons… → a few of these LLPs will decay in ATLAS or CMS! LHC Main detectors are limited in their ability to probe *very* long neutral LLP lifetimes. Obvious reason: Geometry But…

Assume ULLPs are produced in exotic Higgs decays with Br ~ 10%

Assume a lifetime near the BBN limit: c� ~ 107m The LHC makes a lot of Higgs bosons… → a few of these LLPs will decay in ATLAS or CMS!

So the detector size is not the (only) limiting factor… LHC Main detectors are limited in their ability to probe *very* long neutral LLP lifetimes.

(Slightly) less obvious reason: Background

For a single (inclusive) single DV in the ATLAS Muon System, the QCD background “cross section” is O(100 fb).

To detect LLPs near the BBN limit, we need a zero-background environment! John-Paul Chou David Curtin MATHUSLA Henry Lubatti 1606.06298

MAssive Timing Hodoscope for Ultra-Stable NeutraL PArticles MATHUSLA Surface Detector

200m

100m 20m Surface Detector

100m (side view)

Dedicated detector for ultra-long-lived particle (ULLP) decays.

~5% geometric coverage.

Removed from LHC interaction point: can be background-free! Example of Achievable Sensitivity For LLP production in exotic Higgs decays: Get close to BBN limit!

mX = 5 GeV mX = 20 GeV mX = 40 GeV MATHUSLA ATLAS (4 events) (exclusion)

104 Comparison: 0.100 h→invis 103 HL-LHC limit 102 0.001 ) ) fb 10 ( XX XX → ->

1 h

h -5 (

10 →

-1 pp Br 10 σ -2 -7 10 10 s = 14 TeV -3 -1 10

3 ab BBN Limit

Decays dominantly in Main Detector 10-4 10-9 0.001 0.100 10 1000 105 107 cτ (m) 3 orders of magnitude better than ATLAS search for single DV in MS Build this for the HL-LHC Upgrade!

200m

100m 20m Surface Detector

100m (side view)

Crazy Expensive? Nope! Hallow! Air-ﬁlled! Room-Temperature! Low-rate high-threshold environment. Only the outside area of the detector volume needs to be instrumented with relatively simple detectors. Design Sketch

SM decay Passing products SM particle(s) RPC layers 20m Air Scintillator

invisible 200m LLP Layers of RPCs in the roof act as a directional tracker. Scintillators give additional veto. ~ns timing, ~cm position resolution.

Reconstructed vertex and time-of-ﬂight measurement of ﬁnal states distinguishes LLP decay from passing cosmic rays, neutrino scattering

Preliminary estimates: sensor cost of O(20 million USD) To Do: Experiment: Build Prototype: In talks with various experimental/hardware groups. Required to validate design, background estimates, etc.. Aim: take test data & write letter of intent 2017!

Theory: Make more detailed physics case: Editors: DC, Matthew McCullough, Patrick Meade, Michele Papucci, Jessie Shelton With contributions from the theory community… Aim: release comprehensive report early 2017!

Experimentalists & Theorists: want to help? Contact us! Conclusions Long Lived Particles are ubiquitous in BSM theories, but have received less phenomenological attention (harder to model for theory community?)

Much progress in developing LHC searches, but still LOADS left to do & many channels to cover.

The long lifetime frontier requires a dedicated detector add-on for the LHC: MATHUSLA!

Other questions/motivations/signatures? Backup Available Space

ATLAS need ~ one nearby farm plot

CMS Achievable Sensitivity

MATHUSLA is sensitive to any produced neutral LLPs!

How to nail down production mode?

Inclusive VBF/Vh trigger at LHC could “tag” MATHUSLA events as “invisible” Higgs decays.

Could check whether signals in MET searches really are dark matter! Available Space

Geometry is very ﬂexible!

Could have distributed design, even split between ATLAS and CMS sites!

(top-down view)

70m

100m Aside: Start Planning for 100 TeV!

Main 40m Forward 25m When digging a new tunnel, Detector Detector cavity for dedicated ULLP 10m 8m 5m detector carries very little additional cost! 20m 20m 40m

(side view)

mX = 5 GeV mX = 20 GeV mX = 40 GeV MATHUSLA Forward Detector

105 0.100 TLEP h→invis limit 104 3

Compact sub-surface 0.001 10 ) fb design can achieve 102 ( XX → -5 10 h much better sensitivity 10 → pp for 4 events in detector

1 σ than TLEP for any ULLPs ) XX -7 10-1 10 s = 100 TeV ->

from exotic Higgs decays h -2 ( -1 10

30 ab BBN Limit Br Decays dominantly in Main Detector -3 10-9 10 0.001 0.100 10 1000 105 107 cτ (m)